Gang,

Today I pumped 15.2 gallons into the tank. Never pumped that much gas into my bird at one time. ....original 1968 tank. How close was I to running out of gas?

close enough to suck the scum off the bottom of my tank

I believe .8 gallons. I've only been able to get 15 gallons in and it was below empty.

Was it a Taliban gas station, they make the pumps read more than you really get!

3.3 gallons

as the 18 gallon tank never holds 18 gallons but closer to 15-16 you were VERY close....the three times I ran out of gas in my car 9 yrs ago, I could only fill just at 15...-15.5

the tank WILL hold 18 gallons of AIR though! lol

I thought you said 2.8 gallons last night.

both are incorrect for gas....but for 'air'....2.8 might be correct

It depends. My bone dry gas tank holds 15.3 gallons of gas. It has an 18 gallon displacment, but that doesn't mean that it holds 18 gallons. If it were my tank, it would have had 1/10th of a gallon.

They were designed with a certain amount of tilt, with the 9 having the largest air bubble. The volume is verified by other by other 9 owners at around 1/10th + -.

The tilt in the install was intentional: NHRA required vehiles to have at least an 18 gallon tank, and it had to be full when drag raced. The semantics comes into play on the definition of full.

Full was defined as up to the fill neck and made no mention of volume, meaning it was legal to have a 5 gallon buble of air in the tank when leaving the line.

Also, it will suck the scum off the bottom even when it's full. My quiestion is why would there be scum in bottom of the tank? It would have to be a real [censored] owner to have such a condition.

Although the tank is 18 gallon capacity, the amount they hold must vary by vehicle.

I looked back at some of my old (1980's) gasoline credit card receipts and found several fill-ups in the 16's to the low-17's.

Temperature is a factor as well in so far as how much you can get in your tank at any given time.

Don't forget that back in the day before the electronics came in, like the old Tokheim pumps, the calibration from pump to pump and station to station was questionable. We had 2 Union 76 stations and the dept of weights and measures was out about twice a year to check calibrations on the pumps...we never had issues but they routinely "tagged out" pumps at other stations(mostly Arcos)for being off. All stations, in Cali anyway, are equipped with tamperproof electronics nowadays.

lol @ Amervo,

I don't know how accurate my gauge is, but I pumped 13.37 gals sunday and was below a quarter, and also hit empty on a couple of hills...

driving back to the fuel depot, all I could think of was "I hope there is no crap sitting on the bottom of the tank"

Used to run my 67 at the track. When running, had maybe 2 gallons in a fuel cell in trunk and the main tank empty. I would run at tracks quite a distance away and would carry five 5 gallon cans with 110 and 94 as I blended. I usually had 2-3 gallons left in 1 can which leads me to believe 18 gallons to be accurate. The fuel gauges in these cars are not accurate for one and usually calibrated to read less than what is actually in tank.

My T/A and my Cavalier read empty with needle on the line, yet when I fill to full, there is usually a 2 gallon difference between capacity and needle registering completely E on the gauge. I will fill with 12 gallons with a capacity of 14.5 gallons.

I believe it is a positive margin of error so people don't totally run their tanks dry.

Some day I'll give a darn and take another crack at fixxing the gauge/sending unit. Till then, that one-gallon can in the trunk is my best buddy.

I dont trust the gauge...I fill up when it gets close to empty ,which is usually at the point I can get 12-13 gals in it....

but the pumps are pretty accurate and when I`ve been empty , meaning the car died from no gas...i`ve filled up with 2 gallons from a plastic tank then gotten about 13 more at closest gas station , equalling 15 gals +-, of course mine is also a 69 which has different filler neck.

Isn't this an episode of Seinfield, where Cramer tries to go as far as he can on a tank of fuel while test driving a car!!! the challange can get addictive

Could be but the receipts I mention in the 16 to low 17's range are from 10 fill-ups at 3 different stations. Even on the recent Cannonbird Run, when I avoided running the guage below the empty mark (something I often did when not in the middle of nowhere Iowa or Nebraska) I had fill-ups of 15.003 and 15.322 gallons along I80 last month. (Plus, I had already put almost .1 gal of additives in before each fill-up and did not fill to the point of visible full to avoid expansion issues in the heat.)

I guess the bottom line is, just stop at about a 1/4 tank and fill'r up, don't worry, be happy

amen

well, if you dont "keep up"...as Andy found out on our way back from Cannonbird Run....I was with Stacy who trailered his with his diesel truck, (big tank)and Carl in his later model TA and we were running about 80 mph towards N Mexico...when I looked down, saw I was below 1/4 tank, I knew that Andy had to be low as he seemed to get lesser gas mileage than I at the time....I sped up next to Stacy , pointed to my tank , yelled "GAS"! we were just at mile marker/exit 11, we exited, filled up...expected Andy to pull in at any time as we thought he would have seen us pulling off....about that time his daughter called ,she was in the Jeep back up car...Andy had hit that big uphill going out of Colorado...ran dry....
so we got back on the road about 2,3 miles there he was....his daughter had run up ahead to get gas, then we could fill up, keep going...

I KNEW he was getting low, he wasnt sure! LOL

WHen I get up around 80mph in my car I can actually watch the fuel gauge move. Not to mention my rpms are pretty high. I haven't went below 1/4 tank yet but only able to get 12 gallons appr. in my tank to fill back up.

Not only are these cars thirsty but I've always thought that with that gas guage being so big that even a small drop shows up easier to the eye.

I`m getting about 14 mpg at 70...a "little less" at 80-90 LOL..9 around town....but they are SMG = Smiles per gallon!

Does anyone else have this issue, when I'm driving the car wants to pull right...at every gas station

I definetly noticed that I need to fill the '68-400 up quite a bit faster than the '67-326. I drive them both pretty low intensity, so I know I'm not burning up the track or anything. Never actually checked the MPG on either one. It's all for enjoyment anyhow. Maybe a half-dozen fill-ups per season.

I just picked up a Garmin Nuvi 205W. It has a pretty cool speedo and odometer function on it. I've known my speedo has been off for a while due to rearend gear change. I installed an adapter a couple of years ago and got it closer, now I've verified I'm 3-4 miles/hour slow on the low end and 5-6 slow at the top end. Better than I had thought. I'll have to fill up and take a road trip with GPS and find out what my actual MPG is.

http://cgi.ebay.com/BRAND-NEW-GARMIN-NUV...=item35ac55ba64

Those gas gauges are indeed rough and should not be trusted too much!
But as Banshee said, they most often reads a little lower, but still you have to find out what is true with YOUR car!
I guess the only way to find out is to run empty, and then measure the fill-up...
Bring a 2 gal. extra can in the trunk for that excersise....:)

BTW; my '94 Eldo reads empty, and I'll get all kinds of warnings, and then it is approx 5 gallons left!! Now, that's being on the safe side!!

my old 67 Mustang I had long ago read 1/4 tank when it was empty! took running dry twice before I learned....

and my 65 Malibu had E I 1/2 I F on it...after running dry once I learned the I next to E was Empty and the I next to F was Full, not any 1/4 marks! LOL

Thats why I like the .256 RE...I am getting on a level cruise close to 20 mpg, mind you when I goose it or hit the hills it drops RADICALLY.

I'm running a stock engine with LBM's and 2.5 inch pipes.

I rarely top it right off as it tends to spit back and all over my shiny bumper etc.. LOL

Wow. What kind of gas cap do you have? I was always concerned about this happening, but after filling very full a few times, no issues like that ever occurred. I have stock gas caps on both cars.

I think what Dave is saying is that when he is filling up it splashes out. Same thing happened to me the first couple of times.

Oh, I get it. I found if I keep the pump nozzel pushed in as far as it can go and hold it tight to the car, I don't get any back-wash. When I used to keep it looser and tipped down a bit, I'd get some wash too.

I've used Holley, QJet and Themoquad carbs in the past. Holley uses the most gas and the Thermoquad uses the least.

Holley - 10-12mpg
Qjet - 14-16mpg
Thermoquad - 13-24mpg

The 24mpg is highway driving @3000rpm's, 70mph.

The thermoquad has small primaries and large secondary's.

Heya Gus, what rearend and tranny are you running?

3.55 Safety track (ZN)

I run a Holley 650, get 14 mpg.....Q-Jet ,you need like 22 tools for to adjust...lol

Going to Cannonbird 17.5 MPG, returning 19.5.

I need to find out my average mpg. I was told my rearend is 3.23 posi trac but haven't verified the ratio yet. Driving to dayton my rpm seemed a little high for that gear ratio. Maybe a winter project?